Advancing Biomimetic Functions of Synthetic Cells through Compartmentalized Cell-Free Protein Synthesis.

Synthetic cells are artificial constructs that mimic the structures and functions of living cells. They are attractive for studying diverse biochemical processes and elucidating the origins of life. While creating a living synthetic cell remains a grand challenge, researchers have successfully synthesized hundreds of unique synthetic cell platforms. One promising approach to developing more sophisticated synthetic cells is to integrate cell-free protein synthesis (CFPS) mechanisms into vesicle platforms. This makes it possible to create synthetic cells with complex biomimetic functions such as genetic circuits, autonomous membrane modifications, sensing and communication, and artificial organelles. This Review explores recent advances in the use of CFPS to impart advanced biomimetic structures and functions to bottom-up synthetic cell platforms. We also discuss the potential applications of synthetic cells in biomedicine as well as the future directions of synthetic cell research.

Comprehensive review of a large cohort of outpatient versus inpatient open renal and bladder surgery in children.

INTRODUCTION: Outpatient surgery and pediatric ambulatory surgery centers continue to have increasing popularity among pediatric urologist for minor surgeries. Past studies have shown that open renal and bladder surgeries (i.e. nephrectomy, pyeloplasty and ureteral reimplantation) can also be done in an outpatient setting. With health care costs continuing to rise, it may be reasonable to explore performing these surgeries as an outpatient and consider performing them in a pediatric ambulatory surgery center. OBJECTIVE: Our study assesses the safety and utility of outpatient open renal and bladder surgeries in children compared to those done as inpatients. STUDY DESIGN: IRB-approved chart review was performed on patients undergoing nephrectomy, ureteral reimplantation, complex ureteral reimplantation, and pyeloplasty by a single pediatric urologist between January 2003-March 2020. Procedures were performed at a freestanding pediatric surgery center (PSC) and a children's hospital (CH). Demographics, type of procedures, American Society of Anesthesiologists score, operative times, time to discharge, ancillary procedures, readmission or ER visits within 72 h were reviewed. Home zip codes were used to determine the distance from pediatric surgery center and children's hospital. RESULTS: 980 procedures were evaluated. Of these, 94% procedures were performed as an outpatient and 6% procedures were performed as inpatients. 40% of patients underwent ancillary procedures. Outpatients had a significantly lower age, ASA score, operative time, and readmission or return to ER within 72 h (1.5% vs. 6.2%). Twelve patients were readmitted (9 outpatient, 3 inpatient) and six returned to the ER (5 outpatient, 1 inpatient). 15/18 of these patients underwent reimplantations. Four required early reoperation on postoperative day (POD)2-3. Only one outpatient reimplant was admitted one day later. PSC patients lived farther away. DISCUSSION: Outpatient open renal and bladder surgery was found to be safely performed in our patients. In addition, it did not matter whether the operation was done in the children's hospital or pediatric ambulatory surgery center. Since outpatient surgery has been shown to be significantly less expensive than inpatient surgery, it is reasonable for pediatric urologist to consider performing these operations in the outpatient setting. CONCLUSIONS: Our experience shows that an outpatient approach to open renal and bladder procedures is safe and should be considered when counseling families about treatment options.

Temperature-responsive membrane permeability of recombinant fusion protein vesicles.

In this study, we investigate the changes in the permeability of the recombinant fusion protein vesicles with different membrane structures as a function of solution temperature. The protein vesicles are self-assembled from recombinant fusion protein complexes composed of an mCherry fused with a glutamic acid-rich leucine zipper and a counter arginine-rich leucine zipper fused with an elastin-like polypeptide (ELP). We have found that the molecular weight cut-off (MWCO) of the protein vesicle membranes varies inversely with solution temperature by monitoring the transport of fluorescent-tagged dextran dyes with different molecular weights. The temperature-responsiveness of the protein vesicle membranes is obtained from the lower critical solution temperature behavior of ELP in the protein building blocks. Consequently, the unique vesicle membrane structures with different single-layered and double-layered ELP organizations impact the sensitivity of the permeability responses of the protein vesicles. Single-layered protein vesicles with the ELP domains facing the interior show more drastic permeability changes as a function of temperature than double-layered protein vesicles in which ELP blocks are buried inside the membranes. This work about the temperature-responsive membrane permeability of unique protein vesicles will provide design guidelines for new biomaterials and their applications, such as drug delivery and synthetic protocell development.

Selectively Depolymerizable Polyurethanes from Unsaturated Polyols Cleavable by Olefin Metathesis.

This communication describes a novel series of linear and crosslinked polyurethanes (PUs) and their selective depolymerization under mild conditions. Two unique polyols are synthesized bearing unsaturated units in a configuration designed to favor ring-closing metathesis (RCM) to five- and six-membered cycloalkenes. These polyols are co-polymerized with toluene diisocyanate to generate linear PUs and trifunctional hexamethylene- and diphenylmethane-based isocyanates to generate crosslinked PUs. The polyol design is such that the RCM reaction cleaves the backbone of the polymer chain. Upon exposure to dilute solutions of Grubbs' catalyst under ambient conditions, the PUs are rapidly depolymerized to low molecular weight, soluble products bearing vinyl and cycloalkene functionalities. These functionalities enable further re-polymerization by traditional strategies for polymerization of double bonds. It is anticipated that this general approach can be expanded to develop a range of chemically recyclable condensation polymers that are readily depolymerized by orthogonal metathesis chemistry.